Vibrance
by GoldExorcist4729
Summary: We know about Gehenna and Assiah and demons and humans, but what about angels? God sends a goblet of golden fire down to Assiah to choose someone to either permanently split the three dimensions, or bring them all together. By chance, this chosen one also happens to be the son of Satan and the guardian of Assiah, Yuri. Will Rin fuse the dimensions, or forever split them apart?
1. Heavenly Spirits

_Disclaimer: I do not own Blue Exorcist/Ao no Exorcist._

* * *

 _Thwack!_ The meaty thud of flesh hitting flesh reverberated through the tennis court, which was empty, save for four teenage boys and three dead pigeons. A boy with lavender-colored hair so pale that it appeared to be a shade of white crumpled to the ground under the force of the black-haired boy's blow. Okumura Rin glared down at his classmate, Shiratori Reiji.

Reiji and his cronies had been shooting pigeons with Reiji's new crossbow when Rin had arrived, and the sight of blood and death had driven him over the edge. Rin couldn't _stand_ blood. He would _not_ tolerate unnecessary death.

Jet black hair waved in the feeble breeze and deep blue eyes narrowed threateningly at the group of rich kids. Reiji shuddered. Scooting backward to get as far away from Rin as possible, the delinquent tenderly touched his bruised cheek.

"Go."

That was the only word that Rin had to say to send the three gangsters running in terror, screaming their heads off all the way down the road and out of sight. The teenager's eyes were shaded from view and he silently watched them flee.

"Am I really a monster?" Rin asked the only surviving pigeon. The pigeon tilted its head sideways in question, "I mean, I just sent them screaming in terror," He shrugged, "So doesn't that make me the bad guy?"

The pigeon cooed in a comforting manner and seemed to make a negative sound, "Good," Rin nodded to the white bird, and it nodded back, taking off and cooing gratefully. The teen watched the bird fly until it was but an invisible speck in the sky, "'Cause I don't wanna be a bad guy."

He looked down at his hands, which were coated in a thin sheen of blood. The ravenette winced and let his hands fall to his sides, "Shit."

Grimacing, he trotted off to the woods to wash his hands in a stream. If he went back to the monastery, his brother would ask him what had happened. If he went to a local shop, they would probably call the police after seeing that the blood wasn't his own. So the nearby forest was the best option. Besides; taking walks helped to clear Rin's mind.

The leaves of late summer were quite a sight to behold with the sun shining through them and illuminating the trees. A dry crunching noise came from the first falling leaves on the ground and he heard birds twittering cheerfully in the canopy. He arrived at the small creek in a matter of minutes and sighed in relief when he felt the dried blood rinse off of his hands. Taking a moment to appreciate the beauty of the woodlands, he soaked in the sun's dying rays as it sank below the horizon. Suddenly, a strange golden glint caught his eye, and he turned to face the source.

Rin gasped in shock. It was a wooden goblet with _golden fire_ in it, and it was _floating_ above the brook. He stared at it, slack-jawed for several seconds, and then he held his hand up to his chin and seemed to ponder something. With a wide grin, he eagerly reached out to touch it, as something about it drew him in, and then a golden flash of light blinded him for a second. He reached up and grabbed it out of the sky -it seemed to be weightless and would just stay in the air unless an outside force acted upon it- and held it in his hands. Sitting down with his back against a tree, he stared deeply into the golden flames and felt a strange pulling sensation in his mind before he blacked out.

The last thing he thought before he was pulled into oblivion was, 'This thing is so fucking awesome.'

* * *

When he woke up, he was no longer sitting by the creek with the goblet in his hands but was instead in a _very_ strange clearing in the middle of a seemingly infinite forest. It appeared to be split in half like a yin-yang circle, but half was blue instead of black and the rest was gold instead of white.

Rin looked to the blue side first. In the sky above it was a full blue moon, and it looked to be nighttime. The grass was dark green but looked like an ethereal shade of midnight blue in the strange light, and on the larger side of the yin half was a pool of golden water; the same shade of the fire in the goblet. Dark-leaved evergreen trees stood in silent vigil around that half of the clearing.

Rin looked at the other side as well. The sun shone in the afternoon sky, and the grass was a shade of yellow not unlike the autumn. The trees were orange and gold, and like the yin side, the yang side had a pool of water; only this one was blue. It looked less ethereal than the blue side, but none the less pretty. It stood in stark contrast to the darkened yin side.

Splitting the circle through the middle and in the shape of the yin-yang symbol was a small creek, just like the one he was just at. He closed his eyes and breathed in the fresh scent of autumn and the cool breeze of a summer night. There was a massive tree right in the middle; one half was blue-themed and the other half was gold, and that was when Rin spied two figures sitting in it. One was a beautiful lady with teal blue eyes -just like his brother's- and dark brown hair, staring at him with a shocked expression. The man sitting next to her had long white hair and icy blue eyes that seemed to burn with a fierce flame. He seemed less shocked at Rin's appearance and more so that he was in the strange tree in the strange clearing.

"Who are you?" Rin and the lady asked at the same time, pointing accusingly, and they both looked away with red dusting their cheeks in embarrassment.

The white-haired man snorted in amusement, and looked down at Rin, " **I feel like I know you from somewhere,** " He drummed his fingers on the tree branch thoughtfully, " **Like I've met you before, but a long time ago.** "

Meanwhile, the woman gasped, "Rin?"

Rin looked up in shock and then frowned quickly, "Do I know you?"

She looked saddened, "No, you were too young," The woman sighed sadly, "You and Yukio were my sons."

"Wait, you mean-" Rin cut himself off by looking up at her with wide eyes.

"Yes," She smiled sadly, but it was warm, and Rin felt safe, "I am your mother."

* * *

"Wait, so let me get this straight," Rin sighed tiredly, "You're Egin Yuri, mine and Yukio's mother," Yuri nodded, smiling happily, "And you're my father, and you're Satan," Satan nodded regally, "And your spirits were dragged from wherever they were before to me when I looked into the golden fire."

"We think so," Yuri interjected, "We aren't positive."

"Okay… I believe you," Rin sat still for several seconds, and then suddenly stood up and flipped over the imaginary table that they were sitting at. An enraged fire burned in his eyes, "THAT'S BULLSHIT! Did you seriously expect me to believe that?!"

" **Well, now that you think of it, it does sound pretty implausible,** " Satan mused thoughtfully, not at all phased by Rin's outburst, " **Hmm…** "

"But it's true!" Yuri cried, standing up as well, "I'm having trouble believing it too!"

"Not as much as I am!"

"No way!"

A fiery spark erupted between them and they seemed as if they were about to get into a fight when suddenly, a blaze of golden fire appeared. A being with black hair stumbled out unceremoniously but managed to catch himself. He bore an uncanny resemblance to Satan, but with golden eyes, and their auras were quite different. The new person had warmer features and seemed more approachable, while Satan appeared cold and dangerous.

Said cold and dangerous demon narrowed his eyes, " **You,** " He snarled in barely suppressed rage, and launched himself with a shocking speed at the newcomer. The new guy's eyes widened and he just barely managed to dodge the attack, before firing a bout of golden flames at Satan.

" _Wait, brother, let's talk about this peacefully!_ " His protests were ignored as blue flames were shot at him, and his hair was singed. Seeing that Satan would not be negotiating, his features hardened and he seemed to transform into a cold, battle-hardened warrior. They engaged in a fierce battle, and Rin and Yuri let their fists fall and watched with their jaws dropped at the godly fight occurring before their eyes.

Suddenly, Rin's eyes narrowed, and he felt rage boil up within his chest, "WHO THE FUCKING FUCK ARE YOU AND WHAT THE FUCKING HELL ARE YOU DOING IN MY FUCKING HEAD?!"

His shout actually managed to stop Satan and the newcomer in their battle, and they looked at him in unconcealed shock, " _ **What?**_ "

"I _said,_ " Rin snarled, "You are in my head, I don't know why, and I want you to either tell me who you are or get the hell out of here."

Satan, Yuri, and the other man all shuddered before sitting down in front of the rock. Rin climbed up on the rock (suddenly feeling like a god), "So, what's your name? And _no killing!_ " He glared at Satan for the last part.

" _I'm God,_ " The man said nervously.

Satan did not try to kill him, and instead shuddered under the weight of Rin's fearsome glare, " **Hell, kid, you're even more terrifying than your mom when you're mad.** "

"I know," He said dismissively with a wave, not even acknowledging the comment, "What are you doing here?"

" _I sent a goblet of holyfire down to earth to choose someone that would make a suitable vessel so that I could pure Assiah of demons and lock the Gehenna Gate,_ " God gulped, " _It apparently chose you, but instead of just outright possessing you, it dragged the souls of the Gehenna Shugoshin and Assiah Shugoshin to your body to maintain the equilibrium._ "

"A Shugoshin is a guardian deity?" All three nodded, "What are you?"

" _I am the Shamayim Shugoshin,_ " God said.

"And Satan is your brother?"

" **He is not-** " Satan was cut off by a vicious glare from Rin, " **Yes, he is my brother.** "

"So shouldn't Yuri be the sister?" At their confused expressions, he said, "You said she was the guardian of Assiah."

" _Yes, but Yuri-nee-chan is not in her true form,_ " God explained.

"Can you reveal your true form to me?"

Yuri nodded hesitantly and began to transform. Her dark brown hair turned black with white streaks, and her eyes were blue with a burst of gold in the center. Other than that, there was literally nothing different about her. Rin sighed wearily, like an old man that had had far too much excitement for one day, "Well, I'm going home. We'll talk later."

Somehow knowing how to, Rin disappeared from his mindscape and awakened back into the real world. Disoriented, he almost dropped the goblet in his hands. He stared. Now it was a constant battle of cyan blue and bright gold flames. The teenager sighed and wrapped it up in his jacket (the flames did not seem to be able to burn anything) before heading homeward.

It had been a _really_ long day.

* * *

Meanwhile, Fujimoto Shirō unlocked the case which held the Koma Sword, an ancient demon-slaying sword that sealed away the demonic power of Okumura Rin. He looked at the tiny flames leaking from the blade and was extremely confused. Instead of blue, like Satan's flames, they were a constant clash between blue and gold; a vicious tye-dye. He stared for a while, uncertain, and then left the room to go search for Rin. He would have to have a word with Pheles Mephisto, who knew more about demonic nature than any other exorcist, being a demon himself. Shirō sighed. Something had clearly happened, and for once, he had not the knowledge of what it was.

* * *

 _So, let me know what you think! By the way, Rin is thirteen years old in this fic. Please review!_


	2. Demons of Hell

_Disclaimer: I do not own Blue Exorcist/Ao no Exorcist._

* * *

The door to the Southern Cross Boys' Monastery creaked open slowly and a dripping wet Okumura Rin stumbled through the doorway. He looked around cautiously to see if anyone was there and breathed a sigh of relief upon discovering that it was empty. Good. He checked to see if the goblet was safe.

On Rin's way back to the place he called home, the sky had suddenly turned dark and a thunderstorm broke loose. He was soaked to the skin, but for some reason, the goblet seemed to be protected by an invisible barrier of sorts (as was evident by the raindrops bouncing off of its invisible shield). Rin glared at it in envy. The golden flames waved merrily, and the blue ones seemed to laugh.

The thirteen-year-old had long since discovered that the flames had personalities to match their owners, and decided to flip the goblet of fire off before picking it up and sneaking carefully to his room upstairs. He peered inside quietly, where he saw Yukio sleeping on the top bunk of their beds.

"Turn off your light!" He hissed to the flames quietly, and they dimmed considerably. Rin quietly changed out of his soaked clothing and into his nightclothes. He picked up the goblet and climbed into bed, hiding it under his covers, and closed his eyes. Darkness consumed his vision almost instantly, and he fell into a deep slumber.

* * *

"Hey, guys?" Rin appeared in his mindscape and sat on the giant rock, where he observed Satan and God in a heated game of rock-paper-scissors (each on 'their' side of the clearing) and Yuri watching them silently. They all turned towards him, quite a comical sight, "You're all siblings, right?" He asked them. They nodded, "Then why did Satan and Yuri have sex?"

The reactions were hilarious. Yuri was a blushing mess and Satan was gasping and spluttering while God took pictures with a camera that he had procured magically, "We didn't have sex!" Yuri protested, "We did an ancient ritual when Satan was using me as his host to visit Assiah to create life from our blood!"

"So I wasn't born like a normal person?" Rin tilted his head to the side.

Satan seemed to have calmed down enough to glare daggers at God and answer Rin's question, " **No, you were not.** "

"What about Yukio?" Rin asked.

" _From what I know, Yuri made a child with Fujimoto Shirō, but the man hasn't admitted it to anyone,_ " God explained, " _So when they accused him of impregnating Yuri, they were correct in their assumptions. She was about to give birth to Yukio when she created you. That's why your half-brother didn't inherit any of Satan's flames._ "

"So the old fart is Yukio's dad?"

Yuri giggled, "Well, that's one way of putting it."

" **Yes indeed. I wanted to possess him to find a way to visit Assiah, but he'd die too early,** " Satan shrugged.

" _Hey, Rin?_ " God asked, " _So, I was thinking,_ " He sounded quite nervous.

"Well?" Rin asked, "Get on with it!"

" _H-hai! Well, I was wondering, since you were made from Satan and Yuri-nee-chan's blood, and you're all three of our hosts, do you think I could add my blood to your body?_ "

Rin looked startled, "Well, I don't see any reason not to, but we shouldn't do it tonight. How about later on I spend the night in the forest and we do whatever ancient ritual is required there?"

"Woo! Way to maintain the equilibrium!" Yuri cheered, jumping into the air, "It's like everything we do is a pattern!"

Satan sat still, " **Too many patterns. It's like someone's setting us up…** " But his comment went unnoticed and Rin decided to sleep the rest of the night away.

* * *

Morning came much too quickly for Rin's liking and he woke up with a yawn and a stretch as the morning sunlight hit his eyelids. He peered under the sheets for the goblet and picked it up, 'Do I really have to carry this everywhere?'

' _No, actually,_ ' Rin jumped and almost hit his head on the top bunk of his and Yukio's beds at the sound of God's voice in his mind, ' _It's invisible and will follow you around because it can float._ '

"Oh. I forgot," Rin rubbed the back of his head sheepishly, "I didn't know it could be invisible."

Satan sighed, ' **Don't talk out loud, dumbass. People are going to hear you. And yes, unless you want someone else to see it, it will basically be nonexistent to them. They can't hear it, feel it, see it, smell it, taste it, or sense it.** '

'Taste?' Rin scrunched up his nose in distaste.

' **You'd be surprised,** ' Satan said dryly, making no room for comment.

'Okay.'

Rin walked downstairs into the kitchens and opened the fridge to make breakfast, ' **What are you, a housewife? Why in hell are you cooking?** '

'Everyone else sucks at it, so I decided to be good at it,' Rin nodded sagely, and cracked an egg over the flour bowl, 'And besides, it's not like me to sit around and wait.'

'Rin-san?' Rin made a mental sound of acknowledgment (?), 'You do know that upon sensing our power within you, demons, angels, and spirits will either worship you, try to figure out what the hell is going on, or attack you, right?'

Rin frowned and poured the batter in the pan, 'I thought there were only spirits in Assiah, and the demons and angels stayed in Gehenna and Shamayim...'

' _It was like that in the beginning, but all three of us have the ability to open dimensional gates, and whenever we visited another realm on a vacation, demons and angels would escape to Assiah,_ ' God explained, ' _However, angels cannot go to Gehenna, and demons cannot go to Shamayim._ '

'What about the afterlife?' Rin was now flipping pancakes in the pan with practiced skill.

' **Heaven and Hell are connected directly to Assiah,** ' Satan said boredly, ' **If you have more Yin energies in you, you will go to Hell and be reincarnated as a demon in Gehenna. If you have more Yang energies in you, you will go to Heaven and be reincarnated as an angel in Shamayim. If you have an equal amount of each, you will be reincarnated as a spirit in Assiah. When you die as demon, angel, or spirit, you will become a human again.** '

'Why humans, though?' Rin took the pancakes off of the pan and put them on plates, 'Are we, like, special or something?'

'Yep!' Yuri chirped, 'Humans are the only creatures that have the potential to use any sort of kihaku!'

'Why are you taking turns talking to me?'

' **Hmm… Good question.** '

Rin had finished preparing a breakfast of pancakes, bacon, eggs, and orange juice when his half-brother, Okumura Yukio, came down. Yukio looked almost nothing like him (something not entirely surprising), with teal blue eyes, light brown hair, and several small moles on his face. He looked down at Rin, surprised that he was actually awake at nine o'clock in the morning.

"Ohayō, Yukio-nii!" Rin grinned cheerfully, waving at his younger brother.

"Ohayō, Rin-nii!" Yukio greeted, also in a cheerful mood.

"Oi! OLD FART! Get down here!" Rin called as he dealt out the plates.

"Coffee!" Fujimoto Shirō gasped, "Need coffee."

"Here's your coffee, tou-san," Yukio sighed, handing a cup of prepared coffee to him. He drank it down eagerly.

"Ack! It burns! Water!" He cried. He was promptly splashed in the face with a bucket of ice-cold water, "Not like that, baka!"

"But you asked for water!" Rin sang, and sat down in his seat to consume his food faster than humanly possible.

"Wow, Rin, you must be really hungry!" Maruta noted as he walked into the room to eat.

"Eh, not really, I just have some stuff to do," Rin was already finished when Naoya and the other priests arrived, "Gotta go now, bye!" All he left behind was a cloud of dust.

Shirō waited for several seconds before speaking, "Is he gone?" He received a round of nods, "Good. I need to talk to you all," He said in a grim voice.

"About what, tou-san?" Seishirō asked.

"The Koma Sword," He heard a chorus of gasps, "It's been leaking."

"Oh, lord," Said Izumi, "Has Rin shown any signs of demonic influence?"

"Not yet, but that's not even the most peculiar thing about this," The priests frowned at Fujimoto's words.

He pulled out Kurikara from behind him, "Where did you pull that from, tou-san?" Yukio asked.

Shirō looked surprised, "Ya'know, I'm not entirely sure," He shrugged, "Anyway, look at the color of the flames."

The priests and Yukio gasped when they saw the myriad of blue and gold swirling together mysteriously, "But aren't golden flames supposedly the flames of God?"

"Yes, and this sword was not meant to seal away not only demonic powers but all supernatural energies," Shirō sighed, "I believe that somehow, in some way, the spawn of Satan has been blessed by God."

There had been a lot of gasping that day, "W-whatever do you mean, tou-san?" Yukio stammered, "Why would God choose Satan's son?"

"I have no clue," Fujimoto shrugged cluelessly, "Go spy on him and tell me if you find something out."

"Hai!"

* * *

Rin threw open the doors to the monastery, and his jaw cracked the ground when he looked outside. All around flew little black demons, tiny white angels, and random animal spirits.

'What the hell? Why are there so many?!' Rin cried mentally.

' _I already told you, baka,_ ' God snorted, ' _It's because the gates opened, and there are demons and angels everywhere._ '

'But there are so many!'

'Go to the woods and talk to one!' Yuri suggested helpfully, 'You could learn stuff!'

'Okay.'

Yukio took a note of his brother's (he didn't know that Fujimoto was his biological father) shock in the notepad be had brought along and followed him to the woods.

* * *

"Hey!" Rin called to a passing demon. It was about the size of his palm and was pitch black with a spherical body. It had a zig-zagged tail with a tip shaped like an arrowhead, and it had two spikes on its head that looked like cat ears. To top that, it had bright green eyes, tiny fangs, and four little spikes on its underside that looked like they might, in fact, be legs, "I need to ask you a question!"

" **Young Prince?** " The tiny demon looked startled, " **Why do you hold King's power?** "

"He's inside me," Rin explained, "Long story. What are your species called?"

" **We are the Coal Tar,** " The tiny demon said, " **At your service, King.** "

"King? I thought I was Prince," Rin looked thoughtful.

" **You have King's power, and therefore, you are King,** " The Coal Tar bowed as best it could with its tiny body, " **We are kin of Astaroth-sama, the King of Rot.** "

"I thought there was only one 'King,'" Rin frowned.

" **There are eight demon kings, of Earth, Rot, Time, Fire, Insects, Water, Spirits, and Light,** " It yawned, as noon was growing near, " **I must leave, young King. I will surely perish in the sunlight.** "

It floated off without another word, "Hmm…"

Rin yawned and decided that he had gotten up far too early for his liking, "I'm gonna take a nap," He slurred tiredly and leaned against a tree, falling asleep easily.

Yukio, who was not close enough to hear what Rin and the small Coal Tar were talking about, but it was clear that Rin could see it, and was clearly communicating with it. He frowned and noted that he had noticed the Coal Tar's genuine respect and attempted bow. He would have to report this to Fujimoto.

* * *

 _A/N: Rate and Review!_


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